/***************************************************************************
 *   Copyright (C) 2009 by Mushthofa   								*
 *   unintendedchoice@gmail.com   									*
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

/**
 * @file   Literal.h
 * @author Roman Schindlauer, Mushthofa
 * 
 * @brief  Literal class.
 * 
 * 
 */

#ifndef _LITERAL_H
#define _LITERAL_H

#include "Atom.h"

#include <set>
#include <boost/ptr_container/indirect_fun.hpp>
#include <boost/shared_ptr.hpp>

class Literal
{
	public:
		Literal();
		~Literal();
		
		Literal(const Literal&);
		
		Literal(const AtomPtr&, bool naf=false);
		Literal& operator=(const Literal&);
		
		const AtomPtr getAtom() const;
		
		bool isNAF() const;
		
		bool isInfix() const;
		
		bool isGround() const;
		
		void negate();
		
		Literal getPrimed() const;
		
		Literal bindVariables(const Substitutions_t& sub);
		
		
		bool operator==(const Literal&) const;
		
		bool operator!=(const Literal&) const;
		
		bool operator<(const Literal&) const;
		
		std::set<std::string> getVariables() const;
		friend std::ostream& operator<<(std::ostream&, const Literal&);
		void accept(BaseVisitor& e) const;
		
		
	private:
		
		const AtomPtr atom;
		bool isWeaklyNegated;
		
};

typedef boost::shared_ptr<Literal> LiteralPtr;

bool operator<(const LiteralPtr& , const LiteralPtr&);

typedef std::set<LiteralPtr, boost::indirect_fun<std::less<Literal> > > RuleBody_t;

std::ostream& operator<<(std::ostream&, const Literal&);

std::ostream& operator<<(std::ostream&, const RuleBody_t);



#endif
// End

